In a number of imaging applications it is desirable to correlate an acquired image with a previously acquired image or a virtual representation of an object. In some applications it is desirable to correlate a two dimensional image of an object to a three dimensional representation of the object. Conventional automated matching approaches require large processing capacity, which limits the application of this approach.
A number of techniques have been employed to monitor wear and migration of prostheses and bones. A leading technology involves the insertion of reference beads in prostheses and bones so that these reference points may be used when an image is acquired to determine the orientation of the prosthesis or bone. This approach is expensive and difficult for surgeons in requiring a number of beads to be inserted during a procedure. Due to the difficulty and expense this technique can only be used for a limited number of patients.
Various techniques for analysis of two dimensional images, such as x-rays, have been developed. Whilst these techniques enable wear to be calculated for a particular x-ray they rely upon the repeatability of image acquisition, which is difficult to achieve.
In a range of machine vision and robotic applications it would be desirable to rapidly correlate an acquired image of a body with one or more images representative of the or similar bodies. In particular it would be desirable to rapidly correlate an acquired two dimensional image of a body with one or more three dimensional representations of a real or virtual body.
It is an object of the invention to satisfy these needs or to at least provide the public with a useful choice.